In the related art, there is a known robot system with which an article being conveyed by a conveyor or a mark made on the conveyor is imaged, the moving velocity of the article conveyed by the conveyor is detected on the basis of the obtained image, and the position of a robot hand is controlled in synchronization with the movement of the article, thereby gripping the moving article with the robot hand (for example, see Japanese Unexamined Patent Application, Publication No. 2009-28818).
With this robot system, in order to detect the moving velocity of the article being conveyed by the conveyor, when gripping the article with the robot hand, the robot is synchronized on the basis of the moving velocity of another article or mark imaged by an image acquisition means that is positioned on the conveyor on an upstream side of the gripping position, and thus, the articles or marks need to be supplied continuously.